This is a modified version of the kolakoski sequence.
Refer to the problem https://www.mathworks.com/matlabcentral/cody/problems/2371 for the original one.
for this case,
Given a particular initial vector a and length x, generate the kolakoski sequence (first x terms) from that vector.
For example if a=[2,1] and x=10 ; the sequence would look like --
2 2 1 1 2 1 2 2 1 2 2